Single or multiple stage blower and nested volute(s) and/or impeller(s) therefor

Abstract

A double-ended blower includes a blower motor assembly supporting opposed first and second shaft ends. The first and second shaft ends have respective first and second impellers attached thereto and enclosed within first and second volutes, respectively. The first volute is connected to an inlet and the second volute is connected to an outlet. The blower motor assembly is supported in a chassis enclosure and a radially outer inter-stage path is between the first and second volute. The second volute is at least partially substantially concentrically nested with the radially outer inter-stage gas path.

What is claimed is: 
     
       1. A positive airway pressure (PAP) device for generating a supply of pressurized breathable gas for treatment of sleep disordered breathing, the PAP device comprising:
 a blower to pressurize gas, the blower including a motor having a shaft and an impeller provided to the shaft, 
 the impeller comprising: 
 a first radially-inner shroud, the first radially-inner shroud having an outer diameter; 
 a second radially-outer shroud, the second radially-outer shroud forming a center opening having an inner diameter, 
 wherein the outer diameter of the first radially-inner shroud is smaller than the inner diameter of the second radially-outer shroud; and 
 a plurality of vanes extending between the first radially-inner shroud and the second radially-outer shroud, 
 each of said plurality of vanes including a first radially-extending edge including a radially-inner portion in contact with the first radially-inner shroud and a second radially-extending edge including a radially-outer portion in contact with the second radially-outer shroud along an entire radial length of said second radially-outer shroud, 
 wherein a relatively shorter radially-inner portion of the second radially-extending edge is not in contact with the second radially-outer shroud and a relatively longer radially-outer portion of the first radially-extending edge is not in contact with the first radially-inner shroud. 
 
     
     
       2. The PAP device according to  claim 1 , wherein the first radially-inner shroud extends in a plane that is substantially parallel to a plane in which the second radially-outer shroud extends. 
     
     
       3. The PAP device according to  claim 1 , wherein the first radially-inner shroud includes a hub or bushing adapted to receive the shaft. 
     
     
       4. The PAP device according to  claim 1 , wherein each of the plurality of vanes has a width or thickness that is approximately constant from the radially-inner portion to the radially-outer portion. 
     
     
       5. The PAP device according to  claim 1 , wherein each of the plurality of vanes has a height defined by said first and second radially-extending edges that varies at least along a portion thereof. 
     
     
       6. The PAP device according to  claim 1 , wherein an outer diameter of the second radially-outer shroud is larger than an outer diameter of the first radially-inner shroud. 
     
     
       7. The PAP device according to  claim 1 , wherein an outer diameter of the second radially-outer shroud is greater than a maximum radial extent of each of the plurality of vanes. 
     
     
       8. The PAP device according to  claim 1 , wherein each of the plurality of vanes has a stepped transverse edge at its radially outermost end. 
     
     
       9. The PAP device according to  claim 1 , wherein the impeller comprises a polycarbonate material and/or polypropylene material. 
     
     
       10. The PAP device according to  claim 1 , wherein each of the plurality of vanes comprises surface disturbances along trailing edges thereof. 
     
     
       11. The PAP device according to  claim 1 , wherein the first radially-inner shroud is a bottom shroud and the second radially-outer shroud is a top shroud. 
     
     
       12. The PAP device according to  claim 1 , wherein the impeller comprises a molded one piece construction. 
     
     
       13. The PAP device according to  claim 1 , wherein the blower is configured to pressurize gas in the range of 4-30 cmH 2 O. 
     
     
       14. The PAP device according to  claim 1 , wherein the shaft has two ends and at least one said impeller provided to each said end. 
     
     
       15. A PAP system for delivery of pressurized breathable gas to a patient for treatment of sleep disordered breathing, the PAP system comprising:
 a PAP device according to  claim 1 ; 
 a patient interface adapted to form a seal with a patient's face; and 
 air delivery tubing to deliver the supply of pressurized breathable gas from the PAP device to the patient interface.